Audi A3 (5dr) 2005 TFSI Quattro luggage compartment light

[YannisHBG]

Hi all,
New to the forum. The luggage compartment light does not come on when the tailgate is opened and neither is that indicated on the instrument panel that the tailgate is open. Have run an output test on VCDS to check the light and it works fine during the test. I have also changed the lock mechanism (albeit to a used one) since I suspected that it could be the microswitch inside it but no luck. Is there anyone who has encountred this before? Yes it could be that the microswitch on the replacemnt lock is also bad but how can I test that?

Thank you all

 

[Orange225]

Try your rear wiper when the boot is open, if it works then that points to a sensor not recognising it’s open

 

[YannisHBG]

Try your rear wiper when the boot is open, if it works then that points to a sensor not recognising it’s open

Thanks for the reply. Just tried it and the rear wiper works when the tailgate is open...Where is the sensor you are referring to located?

 

[Orange225]

No idea where the sensor would be, but it’s definitely thinking it’s closed, as the wiper shouldn’t work with the boot open

 

[YannisHBG]

Guys this is driving me crazy! Just changed the boot lock to a new one and still no luck. I can open and close the tailgate no problem, but there is no indication on the DIS that the boot is open and the luggage compartment light doesn't come on. Moreover with the tailgate wide open the rear wiper can be operated since the systen thinsk the boot is closed. Help.....

 

[abmat]

Have you had a look at the female side of the locking mechanism? There might be a switch under the flap that gets pushed down by the lock? Long shot but worth a look.

 

[YannisHBG]

Have you had a look at the female side of the locking mechanism? There might be a switch under the flap that gets pushed down by the lock? Long shot but worth a look.

The lock is new (which is the female side) or do you mean the latch attached to the bodywork at the rear?

 

[abmat]

Yes, the latch

 

[YannisHBG]

Yes, the latch

Will give it a shot although I wouldn't expect the latch to serve as a switch. On the same note I ran a diagnostic on a friends laptop and the scan came back with a 00470 error code - Combination Comfort Databus in Single Wire. After different tests unplugging modules I narrowed it down to the J393 convenience module in the boot (passenger side for LHD cars). When I unplug it the system goes back into 2-wire mode. Took it off and noticed that the light brown connector was corroded so sprayed some WD40 on that . I also opened up the module and discovered that there was a big water stain on the PCB that had oxidised some of the components which I cleaned up. Put it back together, no joy but I now suspect that the J393 might have been permanently damaged by the water and since that module controls the lid mechanism, switches and passenger light maybe a replacement is the only solution... But then again when running output tests on the J393 everything seems to work fine....

 

[YannisHBG]

For future reference it was a faulty J393 after all. Picked one up from ebay, recoded and reprogammed it and everything is working as it should now